Apple Macs have long had a reputation for being free of the viruses and malware that often plagues Windows.

But even Apple is now admitting that its customers could benefit from protection from security threats. The company began recommending that users of its Mac operating system to consider using antivirus software in a message on a company support page.

"Apple encourages the widespread use of multiple antivirus utilities so that virus programmers have more than one application to circumvent, thus making the whole virus-writing process more difficult," Apple wrote on its support page.

The note also identifies different vendors with antivirus products available for Macs.

The recommendation from Apple challenges conventional wisdom surrounding Mac OS that it is safer and perhaps immune from virus activities -- a belief supported by the fact that virus attacks on Macs over the years have been almost non-existent.

Still, the threat may be growing as Apple's prominence and market share soar. Symantec, which is one of the antivirus vendors recommended by Apple's support page, has now identified what it claims to be a Mac OS X Trojan Kit. According to Symantec, OSX.Lamzev.A is a Trojan horse that opens a back door on the compromised computer.

The Lamzev.A trojan joins a short list of malware and proof-of-concepts found for the Mac. In 2007, researchers reported the OSX/Pupe Trojan that acted as a malicious DNS changer. At the time, antivirus vendor McAfee said that most Mac customers don't run antivirus software because they are under the impression there are no viruses for the Mac.

A report from security vendor Sophos earlier this year found that in a poll of 350 Mac users, 93 percent believed malware writers would increasingly target the Mac in the future.

Mac Security in the Limelight

Though Apple is recommending antivirus to its Mac OS users on its support page, other Apple Mac materials still boast of Mac's inherent security. "Mac OS X resists most viruses, so you can do anything -- without worrying about losing everything," Apple stated in its Get a Mac FAQ. Still, it shied away from claiming in its FAQ that a Mac is entirely immune to viruses.

"While no computer connected to the Internet is 100 percent immune to viruses and spyware, the Mac is built on a solid UNIX foundation and designed with security in mind," the Get a Mac FAQ states.

Reports from security vendors and Apple's own recommendations aside, Mac users still aren't in the same boat as Windows users. "Certainly, the number of threats for the Mac OS are still small when compared to the hordes of families aimed at more traditional OS targets," Alfredo Pesoli, a security researcher at Symantec, wrote on a company blog last week.

"However, at the moment, it seems as if more malware writers are seeing Mac OS as a world worthy of exploration."